Android global variable

如何在应用程序的生命周期中创建全局变量keep keep values而不管哪个活动正在运行..

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You can extend the base android.app.Application class and add member variables like so:

public class MyApplication extends Application {

    private String someVariable;

    public String getSomeVariable() {
        return someVariable;
    }

    public void setSomeVariable(String someVariable) {
        this.someVariable = someVariable;
    }
}

In your android manifest you must declare the class implementing android.app.Application (add the android:name=".MyApplication" attribute to the existing application tag):

<application 
  android:name=".MyApplication" 
  android:icon="@drawable/icon" 
  android:label="@string/app_name">

Then in your activities you can get and set the variable like so:

// set
((MyApplication) this.getApplication()).setSomeVariable("foo");

// get
String s = ((MyApplication) this.getApplication()).getSomeVariable();

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You can use a Singleton Pattern like this:

package com.ramps;

public class MyProperties {
private static MyProperties mInstance= null;

public int someValueIWantToKeep;

protected MyProperties(){}

public static synchronized MyProperties getInstance() {
        if(null == mInstance){
            mInstance = new MyProperties();
        }
        return mInstance;
    }
}

In your application you can access your singleton in this way:

MyProperties.getInstance().someValueIWantToKeep

---

这个全局变量适用于我的项目：

public class Global {
    public static int ivar1, ivar2;
    public static String svar1, svar2;
    public static int[] myarray1 = new int[10];
}


//  How to use other or many activity
Global.ivar1 = 10;

int i = Global.ivar1;

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